To qualify for the 2-for-1 offers from DayGuidesOutUK, you must have a valid National Railcard photo ID (you must have the photo to-size with you at time of purchase, see website for photo measurements and guidelines) along with a current, non-expired National Rail ticket. If you fail to print vouchers online before your travels, these London 2-for-1 booklets are available at any National Rail counter and contain the same current offers as their website.